DE102008024569A1 - exhaust gas cooler - Google Patents

Abstract

The invention relates to an exhaust gas cooler, which has a housing (15) with a bypass channel (16) and a cooling area (17) in which an exhaust gas cooling channel (18) is arranged, wherein the housing (15) has an actuating element (23) for controlling the Exhaust gas flow either through the bypass channel (16) or through the cooling region (17) and wherein the housing (15) has an exhaust gas inlet region (21) and an exhaust gas outlet region (22).
In order to increase the cooling capacity of the exhaust gas cooler, it is advantageously provided to divert the exhaust gas flow through the cooling area several times, wherein the exhaust gas cooling channel (18) has an inlet cooling channel (25), at least one adjoining deflection channel (26) and a deflection channel (26). adjoining exit cooling channel (27), wherein the exhaust gas flow in the deflection channel (26) opposite to the flow direction of the inlet cooling channel (25) and the outlet cooling channel (27) and wherein the bypass channel (16) of a deflection region (29) of the deflection channel (26) separated is.

Description

The Invention relates to an exhaust gas cooler, the one housing having a bypass channel and with a cooling area in which an exhaust gas cooling passage is arranged, wherein the housing at least one actuator for controlling the exhaust gas flow either by has the bypass channel or through the cooling area, and the case having an exhaust gas inlet region and an exhaust gas outlet region.

such exhaust gas cooler For example, they are used in exhaust gas recirculation systems of internal combustion engines. The cooled Exhaust gas recirculation lowers in particular the output of Nitrogen oxides by reducing the combustion temperature in the cylinders, For example, reduced by diesel engines. For this purpose, a through an exhaust gas recirculation valve Regulated exhaust gas passed after the combustion process through the exhaust gas cooler. Subsequently the exhaust gas is the for needed the combustion process Fresh air supplied. The addition of exhaust gas to the fresh air lowers the oxygen concentration in the cylinders and thus the combustion temperature. The cooling of the Exhaust gases amplified this effect.

If no cooling the exhaust gas is desired, such as during a start or cold start of the internal combustion engine, the exhaust gas is at the cooling area or the exhaust gas cooling channel passed by the actuator releases the bypass channel.

Known exhaust gas cooler or exhaust gas recirculation cooler are z. B. executed in the I-type and, for example, in the U-type, and have only a limited cooling capacity.

at the I-construction is the entrance area at one end of the exhaust gas cooler arranged, as seen in the axial direction at one to the inlet end face opposite Exit end face of the exit region is arranged. The bypass channel runs in Axial direction over its entire longitudinal extent parallel to the cooling area or to the exhaust gas cooling channel. The cooling area or the exhaust gas cooling channel extends axially from the inlet side to the outlet side.

at the U-construction, however, the bypass channel is substantially perpendicular to the cooling area or to the exhaust gas cooling channel arranged, wherein the exhaust gas cooling passage or the exhaust stream a U-shaped course inside the case or the cooling area having.

Of the Invention is the object of an exhaust gas cooler, in particular an exhaust gas cooler for cooling recirculated exhaust gases indicate at which the cooling capacity is considerably improved with simple means.

According to the invention Task by an exhaust gas cooler solved with the features of claim 1, wherein the exhaust gas cooling passage an inlet cooling channel, at least one subsequent to the inlet cooling channel deflection channel and an outlet cooling channel adjoining the deflection channel wherein the exhaust gas flow in the deflection channel in each case opposite to the flow direction the exhaust gases on the one hand in the inlet cooling channel and the other in the outlet cooling channel flows, and wherein the bypass channel of a deflection of the Umlenkkanals means Separating agents is separated.

Advantageous thus becomes an exhaust gas cooler to disposal where the cooling capacity elevated is, since the exhaust gas flow several times, in particular more than twice, preferably four times through the cooling area of the housing is passed when the bypass channel closed via the actuator is. In the meaning of the invention, an exhaust gas cooling passage is the route of the exhaust gases through the cooling area.

Of the Exhaust gas flow occurs the exhaust gas inlet region in the inlet cooling channel, and flows in the direction to a closed end side of the exhaust gas cooler. At the end will be the exhaust gas flow in the direction of the deflection channel or in the direction of a passed first portion of the deflection channel, in which the exhaust gas flow opposite to the flow direction in the inlet cooling channel flows in the direction of the deflection region. End is the exhaust gas flow preferably diverted in a high direction of the exhaust gas cooler. In the deflection area is the exhaust gas stream flowing in from the first section of the deflection channel here in a transverse direction of the exhaust gas cooler seen towards a second section of the deflection channel diverted. In the second section of the cooling channel flow Exhaust gases in the same manner as in the inlet cooling channel towards the closed End side, and are seen here in the vertical direction deflected to the exit cooling channel. In the exit cooling channel stream the exhaust gases opposite to the flow direction of the exhaust gases in the second section towards the exit area, and connect cooled here from the exhaust gas cooler out.

insofar is the to be cooled Exhaust gas stream therefore passed at least four times through the cooling area of the housing, thereby reducing the cooling capacity the exhaust gas cooler, or the exhaust gas cooler for cooling recirculated exhaust gases is significantly increased. Of course, another can Be provided deflecting, so that the exhaust gases the cooling area flow through more than four times.

In a preferred embodiment, it is provided that the respective sections of the Umlenkkanals parallel to a to the inlet cooling channel and to the other to the exit cooling channel. The deflection channel, with its respective sections seen in the vertical direction of the exhaust gas cooler, is arranged in each case below the inlet cooling channel or the outlet cooling channel. Of course, both the inlet cooling channel, the outlet cooling channel and at least the two sections of the deflection channel are surrounded by coolant. Of course, in each case at the end, ie in the end-side deflection region, a coolant flow may also be provided.

Around To avoid the exhaust gas flow from the deflection area into the bypass can reach, the release agent is advantageously provided. The release agent is preferably designed as a partition, which in the vertical direction of the exhaust gas cooler Seen between the bypass channel and the deflection arranged is. The partition preferably extends transversely as seen across the entire width of the housing from the exhaust gas inlet region in the direction of the exhaust gas outlet region.

In advantageous embodiment is provided that the actuating element is arranged in the bypass as well as in the deflection, so is advantageously designed as a double flap element. The actuator is it useful with two flap elements executed, which are arranged on a common flap axis so that the deflection is open when the bypass channel is closed. This causes an exhaust gas flow through the cooling area of the exhaust gas cooler. on the other hand is the deflection area with open Bypass channel closed by means of the flap element, so that the Exhaust gases only through the bypass channel and not through the cooling area stream can. The flap elements are cheaper Way with their inflow surfaces respectively offset by 90 ° arranged on the common flap axis.

In another possible Design can be arranged in the deflection flap element omitted. Here, the actuator is only in the bypass channel arranged, so designed as a single flap element, so that an exhaust gas flow through the cooling area when open Bypass channel is prevented. On the other hand, when closed Bypass duct an exhaust gas flow through the cooling area reached.

The Control element or its flap element can be circular or also square be without the possible To limit embodiments thereof. In the exemplary circular Design, it is useful if the flap axis extends centrally through the flap element. The Flap element can be pivoted so that a passage opened in the bypass channel or closed. Of course this will be optional in The deflecting region arranged flap element pivots accordingly. The passage has both in the bypass channel and in the deflection area cheaper Manner adapted to the flap element sealing wall, to which the flap element in the closed position sufficiently tight invests.

at the exemplary quadrangular configuration, the flap axis eccentrically be installed. The flap axis can either cooling area side or opposite on an outer edge be arranged of the flap element, so that the entire inflow surface of the flap element out of the respective passage out or be pivoted into this sealing can. Of course the flap axis can also run centrally through the flap element, wherein a central course is advantageous in that Flap element is balanced, so in each case on both sides of the valve axis is flowed evenly.

The The invention will be described below with reference to the schematic drawings illustrated embodiments explained in more detail. It demonstrate:

1 an exhaust gas cooler in a first embodiment according to the prior art,

2 an exhaust gas cooler in a second embodiment according to the prior art,

3 off the exhaust gas cooler 2 as a cross section,

4 an inventive exhaust gas cooler in a perspective view,

5 a schematic representation of the exhaust gas flow in the exhaust gas cooler according to 4 .

6 off the exhaust gas cooler 4 with only one flap element, and

7 off the exhaust gas cooler 4 with a further embodiment of the flap element.

1 shows an exhaust gas cooler 1 according to the state of the art in the so-called I-construction. The exhaust gas cooler 1 has a housing 2 with an entry side 3 and an exit side opposite thereto 4 on. At the entrance side 3 Exhaust gases pass through an exhaust gas inlet area 5 in the case 2 one.

In the exhaust gas inlet area 5 is one around the axis 11 pivotable actuator 6 arranged, which the incoming exhaust gas flow either to a bypass channel 7 or to a cooling area 8th of the exhaust gas cooler 1 passes. In the cooling area 8th is an exhaust gas cooling passage 9 arranged, extending from the entrance area 5 towards an exhaust gas exit area 10 or in the direction of the exit side 4 extends. The bypass channel 7 runs parallel to the cooling area 8th or to the exhaust gas cooling channel 9 ,

In 2 is an exhaust gas cooler 12 in the so-called U-construction with a cassette-like housing 13 shown. In contrast to the exhaust gas cooler 1 according to 1 , points the exhaust gas cooler 12 a U-shaped profile of the exhaust gas cooling passage 9 through the cooling area 8th on ( 3 ). The bypass channel 7 is arranged at the front, wherein the actuating element 6 in the bypass channel 7 is arranged.

4 shows an exhaust gas cooler 14 according to the invention. The exhaust gas cooler 14 has a housing 15 with a bypass channel 16 and a cooling area 17 on. In the cooling area 17 is an exhaust gas cooling channel 18 arranged ( 5 ), which is flowed around by coolant. The coolant flows in individual cooling tubes 42 , An exhaust gas cooling channel according to the invention is the path of the exhaust gas flow (arrow 24 ) through the cooling area or through the exhaust gas cooler. The housing 15 , which is designed like a cassette in the illustrated embodiment, has a front side 19 and an opposite end side 20 on. Front is the bypass channel 16 arranged, wherein also front side, an exhaust gas inlet area 21 and an exhaust gas exit area 22 is arranged. The exhaust gas inlet area 21 flows into the bypass channel 16 , wherein the exhaust gas outlet region 22 by way of example opposite the exhaust gas inlet region 21 is arranged.

In the case 15 Front is an actuator 23 arranged, which the exhaust gas flow (arrow 24 ) so that controls this either through the cooling area 17 or the exhaust gas cooling passage 18 or through the bypass channel 16 flows. Is the control element 23 positioned so that the bypass channel 16 is open, the exhaust gases flow through without the cooling area 17 to flow into the exhaust gas inlet area 21 a, pass the bypass channel 16 and flow out of the exhaust gas outlet area 22 from the exhaust gas cooler 14 out.

Is the control element 23 positioned so that the bypass channel 16 closed as example 4 shows, which flow into the exhaust gas inlet region 21 entering exhaust gases in the exhaust gas cooler 14 and flow through the cooling area 17 ,

The cooling area 17 or its exhaust gas cooling channel 18 is designed so that the exhaust gas cooling duct 18 an inlet cooling channel 25 , at least one to the inlet cooling channel 25 subsequent deflection channel 26 and a to the deflection channel 26 subsequent exit cooling channel 27 having. The exhaust gas flow flows in the deflection channel 26 respectively opposite to the flow direction of the exhaust gases on the one hand in the inlet cooling channel 25 and on the other hand in the exit cooling channel 27 , This is basically in 5 shown. The bypass channel 16 is by means of release agents 28 from a front deflection area 29 of the deflection channel 26 separated ( 4 ).

Again 5 can be removed in principle, the exhaust gases flow through a clever deflection within the cooling area 17 example, four times through this, whereby the cooling performance of the exhaust gas cooler, for example, compared to the exhaust gas cooler 12 according to 2 is significantly improved with the same outer geometry.

More specifically, the exhaust gases flow over the exhaust gas inlet area 21 in the inlet cooling channel 25 and stream towards the end side 20 , In the area of the end side 20 the exhaust gases are directed towards the deflection channel 26 or to a first section 30 of the deflection channel 26 directed. In this case, the exhaust gas flow in a vertical direction Y is diverted downward by way of example (arrow 43 ), and thus enters a first section 30 of the deflection channel 26 which preferably parallel to the inlet cooling channel 25 but below this runs. In the first section 30 of the deflection channel 26 the exhaust gases flow in the inlet cooling channel opposite to the direction of flow 25 towards the front deflection area 29 , Here, the exhaust gases are deflected seen in a transverse direction X and enter a to the first section 30 subsequent second section 31 of the deflection channel 26 one. In the second section 31 of the deflection channel 26 the fumes flow towards the end side 20 , So right oriented to the flow direction in the inlet cooling channel 25 , At the end, the exhaust gases in the vertical direction Y are deflected upward (arrow 44 ) and enter the exit cooling channel 27 one. In the exit cooling channel 27 the fumes flow towards the front 20 , ie opposite to the flow direction in the second section 31 of the deflection channel 26 but equally oriented to the flow direction in the first section 30 of the deflection channel 26 ,

The release agent 28 is preferably designed as a partition, which is located between the bypass channel 16 and the front deflection area 29 seen in the transverse direction X throughout the exhaust gas inlet region 21 towards the exhaust outlet area 22 extends ( 4 ). The front 19 is seen in the vertical direction Y almost halved. The upper half of the drawing plane is more or less the bypass channel 16 while the lower half in the plane of the drawing is more or less the deflection area 29 represents, which are preferably separated gas-tight from each other. This exemplary division can also be reversed, so that the lower half of the bypass channel 16 and accordingly the upper half of the deflection area 29 represents. Of course, the release agent 28 or the partition also off-center, so be arranged in the vertical direction Y both downwards and upwards.

In the in 4 illustrated embodiment is the actuator 23 as double flap element 32 executed. The double flap element 32 indicates the bypass channel 16 and a deflection area 29 associated flap element 33 respectively. 34 on. Both flap elements 33 and 34 are exemplary circular in design, and have a common valve axis 35 on. The flap axis 35 is preferably in the middle in both flap elements 33 and 34 inserted and on the housing 15 stored so that the flap elements 33 and 34 can be pivoted into an opening and a closing position. In a favorable embodiment, the two flap elements 33 and 34 with their inflow surfaces 36 arranged offset by 90 ° to each other. This allows the bypass channel 16 be closed so that the exhaust gases flow through the cooling area, while at the same time the deflection area 29 is open ( 4 ). On the other hand, the bypass channel 16 by means of the upper level in the plane of the drawing element 33 be open so that the exhaust gases through the bypass channel 16 can flow, the deflection 29 closed is.

The respective flap elements 33 respectively. 34 lie in their closed position sufficiently close to corresponding sealing walls 37 which clear a passage when the respective flap elements 33 or 34 not present.

Unlike the in 4 illustrated embodiment, the exhaust gas cooler 14 according to the embodiment 6 an actuator 23 on, as a single flap element 38 is executed. Its flap axis 39 is both in the case 15 as well as in the release agent 28 or stored in the partition. This is initially advantageous in the deflection area 29 arranged flap element omitted. Otherwise corresponds to the exhaust gas cooler 14 according to the embodiment according to 6 according to the embodiment 4 ,

In the embodiment too 7 is the control element 23 as a single flap element 40 executed with quadrangular configuration. Its flap axis 41 is as shown preferred cooling area side arranged. By pivoting the single flap element 40 by 90 ° from the in 7 shown position of the bypass is opened and at the same time the cooling area preferably completely closed, wherein the single flap element 40 favorably has a correspondingly adapted flap geometry. Of course, the flap axis 41 but also to be opposite to an outside or centered. Of course, it is within the meaning of the invention, an actuator 23 as a double flap element with each quadrangular flap elements execute.

1

exhaust gas cooler

2

casing

3

Inlet end side

4

Outlet end side

5

Exhaust gas inlet region

6

actuator

7

bypass channel

8th

cooling area

9

Exhaust cooling channel

10

Exhaust outlet area

11

axis

12

exhaust gas cooler

13

casing

14

exhaust gas cooler

15

casing

16

bypass channel

17

cooling area

18

Exhaust cooling channel

19

front

20

end side

21

Exhaust gas inlet region

22

Exhaust outlet area

23

actuator

24

exhaust gas flow

25

Admission cooling channel

26

diversion channel

27

Outlet cooling channel

28

release agent

29

deflection

30

first section v. 26

31

second section v. 26

32

Double flap element

33

flap element

34

flap element

35

damper shaft

36

leading faces

37

cut-off wall

38

Simple flap element

39

damper shaft

40

Simple flap element

41

damper shaft

42

cooling pipes

43

Flow arrow at 20 downward

44

Flow arrow at 20 up

Claims (6)

Exhaust gas cooler, which has a housing ( 15 ) with a bypass channel ( 16 ) and a cooling area ( 17 ), in which an exhaust gas cooling channel ( 18 ), wherein the housing ( 15 ) an actuator ( 23 ) to Control of the exhaust gas flow either through the bypass channel ( 16 ) or through the cooling area ( 17 ), and wherein the housing ( 15 ) an exhaust gas inlet region ( 21 ) and an exhaust gas outlet area ( 22 ), characterized in that the exhaust gas cooling channel ( 18 ) an inlet cooling channel ( 25 ), at least one adjoining deflection channel ( 26 ) and a to the deflection channel ( 26 ) subsequent exit cooling channel ( 27 ), wherein the exhaust gas flow in the deflection channel ( 26 ) in the opposite direction to the flow direction of the inlet cooling channel ( 25 ) and the exit cooling channel ( 27 ) flows, and wherein the bypass channel ( 16 ) of a deflection area ( 29 ) of the deflection channel ( 26 ) is disconnected. Exhaust cooler according to claim 1, characterized in that exhaust gases via the exhaust gas inlet region ( 21 ) into the inlet cooling channel ( 25 ) and towards an end face ( 20 ), wherein the exhaust gas stream at the end side ( 20 ) in the direction of the deflection channel ( 26 ) or its first section ( 30 ) is diverted, in which the exhaust gas flow opposite to the flow direction in the inlet cooling channel ( 25 ) in the direction of the deflection area ( 29 ) flows, wherein the exhaust gas flow in the unlenkbereich ( 29 ) to a second section ( 31 ) of the deflection channel ( 26 ) and towards the end side ( 20 ) flows, where the exhaust gases in the direction of the exit cooling channel ( 27 ) and in this direction towards the exhaust gas outlet area ( 22 ) stream. Exhaust cooler according to claim 1 or 2, characterized in that the deflection channel ( 26 ) with its sections ( 30 . 31 ) parallel to one to the inlet cooling channel ( 25 ) and on the other hand to the outlet cooling channel ( 27 ) runs. Exhaust gas cooler according to one of the preceding claims, characterized in that a release agent ( 28 ) between the bypass channel ( 16 ) and the deflection area ( 29 ) of the deflection channel ( 26 ) is arranged. Exhaust gas cooler according to one of the preceding claims, characterized in that the actuating element ( 23 ) as a double flap element ( 32 ) is executed. Exhaust cooler according to one of claims 1 to 4, characterized in that the actuating element ( 23 ) as a single flap element ( 38 ) is executed.